(a) Field of the Invention
The present invention may relate to a plasma display panel, and particularly to a surface-discharge plasma display panel that may have an electrode structure in which a pair of discharge sustain electrodes may be arranged at respective discharge cells between two substrates to make the display discharge.
(b) Description of Related Art
Generally, a plasma display panel (PDP) may be a display device that operates by exciting phosphors using ultraviolet rays radiated from plasma obtained by discharging an electric current through a gas. The desired result may be red (R), green (G), and blue (B) visible light that may be used to display a desired image. A PDP may be useful as a flat panel display for television and other displays, and may accrue several advantages. For example, a PDP may be able to provide a very large screen of 60″ or more with a thickness of 10″ or less. It may also have excellent color quality and may avoid image distortion due to change in viewing angle because it is a light-emissive display. A PDP may be made in a simplified manner, compared to a liquid crystal display (LCD), and thus may lower the cost of producing a flat panel display.
FIG. 17 illustrates the structure of an exemplary alternating current (AC) PDP. Address electrodes 112 may be formed on a rear substrate 110 in a direction (in the y-axis direction of the drawing), and a dielectric layer 113 may be formed on the entire surface of the rear substrate 110 and may also cover the address electrodes 112. A plurality of stripe-shaped barrier ribs 115 may be formed on the dielectric layer 113 between the neighboring address electrodes 112. Red R, green G, and blue B phosphor layers 117 may be formed between the neighboring barrier ribs 115.
A pair of discharge sustain electrodes 102 and 103 may be formed on the surface of the front substrate 100 facing the rear substrate 110 in a direction crossing the address electrodes 112 (in the x-axis direction of the drawing). The pair of discharge sustain electrodes 102 and 103 may include transparent electrodes 102a and 103a as well as bus electrodes 102b and 103b. A dielectric layer 106 and an MgO protective layer 108 may be sequentially formed on the entire surface of the front substrate 100 and may also cover the discharge sustain electrodes 102 and 103.
The address electrodes 112 may be formed on the rear substrate 110, and the pair of discharge sustain electrodes 102 and 103 may be formed on the front substrate 100 such that the address electrodes 112 and the discharge sustain electrodes 102 and 103 cross each other. The area where they cross may be the discharge cells.
A plurality (for example, millions) of such discharge cells may be included in a matrix form within a PDP. In order to simultaneously drive the discharge cells of the AC PDP arranged in the matrix form, the memory characteristic thereof may be used.
A predetermined voltage may be made to generate the discharge between the X electrode (display electrode) 102 and the Y electrode (scan electrode) 103. The X electrode (display electrode) 102 and the Y electrode (scan electrode) 103 may be the pair of discharge sustain electrodes 102 and 103. The critical voltage of such a discharge may be the firing voltage Vf. The address voltage Va may be applied between the Y electrode 103 and the address electrode 112, and the discharge may occur forming plasma within the discharge cells. This may occur because the electrons and ions in the plasma shift toward the electrode with opposite polarity, thereby permitting the flow of electric current.
The dielectric layers 106 and 113 may be formed on the respective electrodes of the AC PDP. Most of the charge carriers (for example, electrons or ions) may be deposited on whichever of dielectric layers 106 and 113 has polarity opposite that of the charge carrier. The net potential (after this deposition) between the Y electrode 103 and the address electrode 112 may be smaller than the originally applied address voltage Va. Thus the discharge may weaken, and the address discharge may dissipate. In such a case, a relatively small amount of electrons may be deposited on the X electrode 102, and a relatively large amount of ions may be deposited on the Y electrode 103. The charges deposited on the dielectric layer 106 covering the X and Y electrodes 102 and 103 may be the wall charge Qw. The space voltage formed between the X and the Y electrodes 102 and 103 due to the wall charge Qw may be the wall voltage Vw.
Assume that a predetermined voltage being the discharge sustain voltage Vs may be applied between the X and the Y electrodes 102 and 103. In such a case, the sum Vs+Vw of the discharge sustain voltage Vs plus the wall voltage Vw may be higher than the firing voltage Vf. Accordingly a discharge may occur within the discharge cell, generating vacuum ultraviolet light (VUV). The VUV light may excite the relevant phosphors, and those phosphors may emit photons of visible light through the transparent front substrate.
However, if any address discharge is not made between the Y electrode 103 and the address electrode 102 (for example, the address voltage Va may be not applied thereto), no wall charge may be deposited between the X and Y electrodes 102 and 103. As a result, no wall voltage Vw may exist between the X and Y electrodes 102 and 103. In such a case, only the discharge sustain voltage Vs applied between the X and Y electrodes 102 and 103 may be made within the discharge cell. As the discharge sustain voltage Vs may be lower than the firing voltage Vf, no discharge may occur in the gas space between the X and Y electrodes 102 and 103.
With the above-structured PDP, several operational steps may be performed between the power inputting and the obtaining of the visible rays. The energy transformation efficiency of the PDP at the respective steps may be not good, and hence, the efficiency of the currently available PDP (the ratio of brightness to power consumption) may be lower than the CRT. For example, the PDP involves disadvantages of high power consumption and significant heat generation.
Particularly with the PDP having an High Definition grade high resolution region of 40″ or more, it may be important to reduce the power consumption. In order to solve such a problem, it may be proposed to lower the discharge voltage through enhancing the electrode structure. For instance, Japanese patent publication No. 2002-008549 discloses a PDP in which the transparent electrode for the discharge sustain electrodes may be mesh-shaped with a plurality of opening portions. Japanese patent publication No. 2001-243883 discloses a PDP in which a pair of bus electrodes for the discharge sustain electrodes may be correspondingly provided at the respective discharge cells, and transparent electrodes may protrude from the bus electrodes inwardly and outwardly. However, with such techniques, the discharge voltage may be not sufficiently reduced, and hence, the problem of high power consumption may be not yet solved.